1.Field of the Invention
This invention relates to a data recording method and a data recording medium for sharing, for example, data on an optical disc of the ISO format and data on an optical disc of the CD format.
2. Description of the Prior Art
The format of continuous servo type optical discs of 3.5 inches and 5 inches is standardized by ISO (International Organization for Standardization). Optical discs of the ISO format have now been put in use as an external storage device of a computer.
On the other hand, paying attention to a CD (compact disc) being a recording medium capable of storing a large amount of data, optical discs (CD-ROM, CD-I, and so forth) for storing data in the CD format have already been spread. Therefore, two kinds of optical discs in a general classification, optical discs of the ISO format and optical discs of the CD format, are currently distributed.
An optical disc of the ISO format and an optical disc of the CD format are completely different in format. Therefore, when it is intended to share data on a disc recorded in the ISO format and data on a disc recorded in the CD format, an inconvenience occurs. Since enormous software resources and data resources have already been built by using optical discs of the ISO format and optical discs of the CD format, respectively, it is difficult under the present situation to decide between the two formats of optical discs.
It is therefore desired to develop an optical disc which permits the ISO format and the CD format to be shared.
In the ISO format, for example, the capacity of one sector is 1200 bytes (user data capacity: 1024 bytes) or 600 bytes (user data capacity: 512 bytes). On the other hand, in the CD format, a block consisting of 98 frames is regarded as one sector. The data capacity of one block (sector) is 2352 bytes. When sub-codes are included, the capacity of one block is 2450 bytes, when error correction codes and others are included, the capacity of one block is 3136 bytes, when sub-codes, error correction codes and others are included, the capacity of one block is 3234 bytes.
An optical disc permitting the shared use of the ISO format and the CD format must cope with two kinds of formats which are different in sector size as explained above. More specifically, it is necessary for such a disc not only that each sector of 1200 bytes can be accessed to for performing recording and reproduction of data in the ISO format but also that each sector (block) of, for example, 3136 bytes excluding sub-codes can be accessed to for performing recording and reproduction of data in the CD format.